1. Field of the Invention
The present invention relates to an arrangement for the automatic control over the filling of a dosing or metering container with pourable or flowable material from a supply container, in a manner, such that a predetermined portion of the pourable material stored in the dosing container is withdrawn from the dosing container and a corresponding quantity of pourable material is automatically refilled into the container.
2. Discussion of the Prior Art
In the industrialized technology it is quite frequently common to control the withdrawal of pourable material from a container in a manner wherein a discharge cross-sectional area of a supply container is opened for a predetermined time interval, such that the quantity of pourable material exiting from the supply container is essentially obtained from the cross-sectional area of the discharge, the opening period of the discharge, and the flowability of the material. This solution is constructionally simple and dependable; nevertheless, the desired degree of exactness achievable thereby for the quantity of material which exits during each opening cycle of the discharge is, not always adequate. During a number of opening cycles, the flowability of the material can vary and the cross-section of the discharge orifice can itself become smaller through agglomerations of material about the edges thereof, or may change in general. Varying the opening period in a corresponding or compensating manner during a plurality of subsequent opening cycles was heretofore not possible due to a lacking correlation in the relationship among the three essential parameters.
For example, the achievable degree of preciseness in the determination of the quantity of material exiting or discharged during each opening cycle is not recommended as being adequate in the foundry or cast molding technology during the formation of molding cores. The strength of the cores, to a high degree, is dependent upon the currently exactly determined, employed sand quantity and the oxygen and moisture content factors.